Alkylation of benzene with olefin of 8 to 16 carbon atoms produces alkylbenzenes that may find various commercial uses, e. g., alkylbenzenes can be sulfonated to produce detergents. As used herein, alkylbenzenes refers to phenylalkanes wherein the alkane group has between about 8 and 16 carbon atoms. Alkylbenzenes are produced as a commodity product in large-scale facilities, e. g. often in amounts of 50, 000 to 200, 000 metric tonnes per year per plant. In the alkylation process, benzene is reacted with an olefin the desired length to produce the sought alkylbenzene. The alkylation conditions comprise the presence of homogeneous or heterogeneous alkylation catalyst such as aluminum chloride, hydrogen fluoride, silica alumina or zeolitic catalysts and elevated temperature.
The alkylbenzene must meet stringent product specifications to be commercially acceptable. For instance, alkylbenzenes, to be desirable for making sulfonated surfactants, must be capable of providing a sulfonated product of suitable clarity, biodegradability and efficacy. The benzene content of the alkylbenzene product should be relatively free from benzenes, e. g. less than about 1 part per million by weight (ppmw), and often less than about 0.5 ppmw. Also, desirable alkylbenzene products are relatively free, e. g., less than about 50, preferably less than about 5, ppmw, from byproducts such as dialkylbenzenes, oligomers of olefins, and the like (herein referred to as “heavies”). Additional considerations for commercial alkylbenzene products include the 2-phenyl content and linearity of the alkyl substituent. With respect to efficacy, alkylbenzenes having higher 2-phenyl contents are desired as they tend, when sulfonated, to provide surfactants having better detergency but less solubility if the 2-phenyl content becomes too high. Thus alkylbenzenes having a 2-phenyl isomer content in the range from about 25 to about 40 percent are particularly desired.
The production of detergents involves a lot of resources, and with the demand for high quality detergents, there is a continuous need to improve the processes for producing linear alkylbenzenes.